def counter(sentence):
    sentence = sentence.replace(',', ' ')
    sentence = sentence.replace('.', ' ')
    sentence = sentence.replace('!', ' ')
    sentence = sentence.lower().split()

    dic = {}

    for word in sentence:
        dic[word] = dic.get(word, 0) + 1
    return dic


print(counter('Good good study, day day up!'));
